One goal in developing a drug is to provide dosage forms which make it possible to maintain a certain amount or concentration of drug in a subject's body that will remain constant for several hours. Often this may not be achieved by traditional rapidly disintegrating tablets, as these tablets release the active ingredient contained therein all at once. For this reason, dosage forms have been developed which are capable of continuously releasing the drug contained therein in a controlled manner and over a prolonged period of time. Oral controlled drug delivery is typically by solid dosage forms including tablets, capsules, microspheres, granules and suspensions.
Gastroretentive systems, drug delivery systems having a prolonged retention time in the stomach, represent a promising approach to controlled release oral delivery of drugs. Many such systems have been developed. For example, U.S. Pat. Nos. 6,635,280 and 6,723,340 describe compositions for gastric retentive tablets which, upon oral administration, swell to a size such that the tablet cannot move out of the stomach easily. The drug is incorporated into a polymer matrix as the tablet swells and is released from the matrix into the gastric fluid by solution diffusion. See U.S. Pat. No. 6,635,280. Thus, the tablet acts as a controlled released gastroretentive system. Other similar gastroretentive systems are described in the art. See, e.g., European Patent No. EP 941071 B1.
A variety of polymeric excipients designed to expand or swell in the stomach have been used for the preparation of gastroretentive systems. See e.g., U.S. Pat. Nos. 6,210,710; 6,217,903; 5,945,125; 5,451,409; 4,915,952; U.S. Patent Publication Nos. 2003/0104053; 2003/0104062; and 2010/0129445. Such systems have been employed for the controlled release of poorly soluble drugs in particular. See, e.g., U.S. Pat. No. 6,635,280 and International Publication No. WO 97/22335. However, there exists a need for alternative controlled release dosage forms for drugs having poor aqueous solubility. Provided herein are controlled release dosage forms addressing this need.